Polymebjzed acetic aldehyde ob acetic acid



a an r.

JOSEPH KOETSCHET AND MAURICE IBEUDET, 0F LYON, FRANCE, ASSIGNORS TO SOCIETE GHIMIQUE DES USINES DU RHONE CARTIER, OF PARIS, FRANCE.

PROCESS FOR THE PRODUCTION OF ACETIC .ANHYDRID I POLY MERIZED ACETIC ALDEHYDE OR ACETIC ACID.

aoaeea.

No Drawing.

lowing is a specification.

It is known from the specification of German Patent No. 28%,996 (Centralblatt l915 2 p. 294) that ethylidene diacetate can be decomposed into aldehyde and acetic anhydrid.

This result is obtained by heating the ethylidene diacetatc at'high temperatures,

with Or without catalyzers. The said specification further states that increase of pressure assists the reaction.

In all these methods of working, the necessity to employ high temperatures is a marked disadvantage. A large quantity of tarry products is produced in the course of the de composition, which reduce the yield enormously and block up the apparatus. Moreover many catalyzers (acids and acid salts) cannot undergo this high heat without decomposition.

The applicants have found that these drawbacks are obviat-ed-whenthe ethylidene diacetate is heated in cacao well below its b0ll1ll omt at atmos heric )ressure 1n presence of acids, acid salts, or other catalyze-rs. 1

yield, without tarring or deterioration of the ca-talyzer.

The remarkable fact is also observed that the aldehyde formed distils in the form of paraldehyde, which offers very important technical advantages from the point of view of the condensation in cacao of the reaction product.

By maintaining the obtained mixture of paraldehyde and acetic anhydrid for a con- Specification of Letters Patent.

he reaction has been found to take place with an approximately quantitative ANCIENNEMENT GILLIAIRD, JP. MONNET ET AND POLYMERIZED OR Non- Ethylidene diacetate 400 parts Sulfuric acid (66 B.) 8 parts is heated at about 70-80 C. at a pressure of. about 100 mm. In two hours 350 parts of a mixture of paraldehyde and acetic anhydrid are collected by distillation.

As the ethylidene diacetate boils at about 115. C. under'lOO mm. pressure, the reaction consequently takes place even beloW the boiling point corresponding to this pressure.

There remain in the apparatus parts of unaltered diacetate and the sulfuric acid introduced at the commencement. On to this residue are charged another 350 parts of diacetate, and the operation can begin again.

The mixture of anhydrid and paraldehyde is treated as before stated.

lVhat we claim "and desire Letters Patent is:

A process of treating ethylidene diacetate, which consists in heating the same under reduced pressure and in the presence of a catalyzer which facilitates formation of acetic anhydrid and polymerized acetaldehyde, to such a temperature that a mixture of acetic anhydrid and polymerized acetalde hyde is produced.

In testimony whereof we have signed our names to this specification.

JOSEPH KOETSCHET. MAURICE BEUDET.

to secure by In the presence of LUCIENNE BoUvEREr, JAMES G. FINLEY.

Patented June 117, 19119. Application filed August 28, 1917. Serial No. 188,556. 

